Electric discharge device



Nov. 2, 19.43. w, H. gENNETT 2,333,145

ELECTRIC DISCHARGE DEVICE Filed July 25, 1941 uvvzzzvz'oie.

WILLARD H. BENNETT ATTORNEY Patented Nov. 2, 1943 ELECTRIC DISCHARGE DEVICE Willard H. Bennett, Newark, Ohio, assig'nor, by 161;:118 assignments, to Games Slayter, Newark,

Ap lication Jul 25, 194:1,Seria1 No. 494,079 g 3 Claims. (or. 250-2745)" This invention relates generally to electric discharge devices of the point-to-plate type and refers more particularly to improvements in grid controlled electric discharge devices.

The invention set forth herein is a continuation in part of the invention disclosed in my copending application, Serial No. 285,635, filed July 20, 1939.

It is one of the principal objects of this in vention to provide a device of the above type wherein the electric discharge takes place in an atmosphere which does not form negative ions or, in other words, in a non-electron attaching gas such, for example, as nitrogen, hydrogen and helium. The operation of the discharge in an atmosphere in which electron attachment to molecules does not readily occur minimizes or eliminates objectionable space charges in the gap and thereby renders it possible to obtain higher operating eificiencies.

Another advantageous feature of this invention which contributes to obtaining higher efilciencies resides in controlling the discharge with a grid predeterminedly located with respect to the discharge electrode or point so that higher inverse peak voltages may be secured Without are back.

A further object of this invention which also contributes to effectively controlling the discharge is to provide an electric discharge device wherein the grid has a large surface area when compared to the cathode or discharge electrode and a small surface area when compared to the collecting electrode or anode. The above construction, together with proper relative positioning of the electrodes, has been found to aiford a controlled diffused discharge in a non-electron attaching gas which is highly efiicient.

Still another object of this invention is to provide a rectification system employing an electric discharge device of the type set forth in the preceding paragraphs.

The foregoing, as well as other objects, will be made more apparent as this description proceeds, especially when considered in connection with'the accompanynig drawing, wherein Figure 1 is a longitudinal sectional view through an electric discharge device constructed in accordance with this invention;

Figure 2 is a cross sectional view taken substantially on the plane indicated by the line 22 of Fi ure 1.

In Figures 1 and 2 of the drawing, I have illustrated an electric discharge device having three electrodes, an emitting electrode 10, a collecting electrode ll spaced from the emitting electrode and a control electrode I2 electrically disposed between the emitting and collecting electrodes. More particularly, it will .be noted that the collecting electrode is in the form of a metal cup having the open end closed by a cap 13 of insulating material and having the exterior of the side walls covered with an insulating material l4 which is shown in the form of a shell integral with the cap. The emitting electrode 10 comprises a rod l5 supported by the cap l3 in concentric relation to the side wall of the cup or collecting electrode H and having a plurality of fine wire points extending radially outwardly therefrom toward the collecting electrode. The control electrode or grid 12 comprises a plurality of bars I 6 also supported within the cup or collecting electrode l l by the cap l3. These grid bars, I6 are spaced circumferentially from each other and are respectively positioned between the extremities of adjacent discharge points in such a manner that the points substantially intersect a geometrical circle which includes the outer surfaces of the grid bars. It has been found that this relative location of the emitter points and grid contributesto obtaining the desired control or" the discharge required to secure higher inverse peak voltages without arc back. This is especially true in the present instance wherein the discharge points have such a small radius of curvature or, in other words, are so fine that the intense electric field is localized at the points and, accordingly, substantially all ionizations are confined to the region adjacent the points.

Another factor which contributes to obtaining the proper discharge is the relative sizes of the electrodes. It will be noted from Figures 1 and 2 that the grid bars have a large surface area compared to the emitter points and a small surface area as compared to th collecting electrode.

With the above construction, the grid acts to substantially suppress currents from the emitter on the inverse half cycle.

Perhaps the most important factor in securing highly efficient operation of the electric discharge device is that the sealed cup-shaped collecting electrode H is filled with a non-electron attaching gas, such as hydrogen, nitrogen, or helium. The interior of the cup-shaped electrode I! is at atmospheric pressure and negative ions are, not formed by the gas. As a result, a much more effective discharge takes place and higher forward or usable currents are obtained for a given Voltage.

2. An electric discharge device comprising a l rod having a plurality of electric discharge points projecting radially outwardly from the axis of the rod in a common plane, a collecting electrode concentric with the axis of the rod and spaced from the tips of said points, control electrodes electrically positioned between the points and collecting electrode in'predetermined relationship to the points, an auxiliary collecting electrode connected to one end of the rod and an auxiliary emitting electrode directed toward the auxiliary collecting electrode and connected to the control electrodes.

3. An electric discharge device comprising in a free electron gas, a collecting electrode, a 00- operating emitting electrode having a fine wire discharge point directed toward the collecting electrode, a grid electrode interposed between the collecting and emitting electrodes, an auxiliary collecting electrode electrically connected to the emitting electrode and an auxiliary emitting point electrode electrically connected to the grid electrode and directed toward the auxiliary collecting electrode.

' WILLARD I-I. BENNETT. 

